Variation Approval Process: A Step-by-Step Guide for UK Builders

A step-by-step guide for UK builders on securing written authorisation for variations, managing JCT contract rules, and maintaining a professional audit trail.

By James Shorter ·

Variation Approval Process: A Step-by-Step Guide for UK Builders

Builder and homeowner review a tile change

A variation is approved when the person named in the contract has authorised it in writing, with scope, price and programme effect recorded, before the work starts. That is the whole process. Everything else is how you make it happen on a live site without losing a day to paperwork.

This guide walks through the steps in order, shows a simple numbering system, covers what JCT contracts say about writing and refusal, and explains how we handle it at BRCKS so the record builds itself while the team gets on with the job.

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TL;DR

  • Get every variation in writing from the person the contract names. A verbal “yes” on site is not an approval.
  • Price it and state the programme effect before starting, using the contract’s own valuation rules.
  • Give each variation one number, one log entry and one folder of supporting documents. Review the log at least monthly.
  • Under JCT, work without a written instruction can go unpaid. Confirm verbal instructions in writing the same day.
  • BRCKS turns a site message into a logged variation, so the trail exists without writing it up at night.

Table of Contents

What counts as a variation

Before you approve anything, you need to know what you are approving. Most construction contracts define a variation, generally as an employer instruction to alter the works or their timing, method or sequence. Not every instruction is a variation, so read the definition in your contract first.

The JCT Standard Building Contract With Quantities 2016 is wide. Clause 5.1 covers changes to design, quality or quantity, including additions, omissions and substitutions. It also covers changes to materials, removal of work already done, and restrictions imposed on access, working space, working hours or the order of work.

That last group catches people out. A client who says “you can’t start before 9” or “do the first floor last” may be varying your contract, even though nothing in the drawings changed.

On a small domestic job with a quote and no standard form, the same logic applies. At common law, there is no inherent right for the client to vary the terms unilaterally. Any change is agreed between both sides unless the contract says otherwise.

The variation approval process, step by step

The sequence below fits most UK residential and small commercial jobs. Adapt the notice periods to your contract.

1. Flag it the day it appears

The change usually arrives as a conversation: the client wants a different tile, the engineer moves a beam, the electrician finds the consumer unit can’t go where drawn. Record it the same day. Note who asked, when, what changed and which drawing or instruction it relates to.

Leaving it until the final account is how disputes start. The CICV best practice note makes the same point: agree variations as they occur rather than leaving the argument to the final account.

2. Get the instruction in writing

If the instruction was verbal, confirm it. The CICV guidance says to request a formal site instruction from the site manager, email the contractor’s QS to confirm it is a variation, give a cost estimate and ask for written approval before proceeding. If nothing comes back, it advises not proceeding unless your subcontract lets you issue a variation notice.

Under JCT, this matters for payment. A variation must be issued in writing to be valid, and contractors are generally not entitled to payment for varied work done without formal instruction, even with verbal approval. Under the older clause 3.12 wording, verbal instructions took effect once confirmed in writing, either by the Contract Administrator or by the contractor, provided the Contract Administrator did not reject the confirmation. These are the Confirmations of Verbal Instructions, or CVIs, you will see on larger jobs.

On a domestic job the equivalent is simple: a text or email that says what is changing, what it costs and that the client agrees. Silence is not acceptance.

2. Get the instruction in writing

3. Assess the change

This is where you work out what the change actually involves. RICS describes the contractor evaluating the change by measuring the elements, making enquiries and considering design and time implications. Ask three questions:

  • What is added, omitted or substituted?
  • What does it do to the programme, and to other trades?
  • Does it need new drawings, a revised RAMS or a building control conversation?

If the change affects the golden thread on a higher-risk building, update the drawings under proper version control too. Our guide to drawing version control covers that side.

4. Price it and state the programme effect

Price it under the contract’s own rules, as a lump sum or in constituent parts. RICS says the pack for each change item should ordinarily include the formal instruction, the legal basis, substantiated quantities and rates (star rates where contract rates cannot apply), a breakdown of labour, materials and plant, drawings, specifications and photos, and a revised programme.

On a small job that is overkill, but the principle scales down. Show the labour, show the materials, show the extra days. If the change moves your finish date, say so on the same page as the price. Pricing and time agreed together is far easier than clawing time back later.

Fenwick Elliott’s advice is to try to agree time, cost and the consequences for other work before the additional work is carried out.

5. Submit to the right person

Send the price to the person the contract names: the Contract Administrator, the employer’s agent, the main contractor’s QS, or on a domestic job the homeowner. The Scottish Government’s change control guidance, written for public projects, says change requests must never go direct to the contractor without going through the change control process. The lesson holds on any job: one entry point, one route.

6. Get a decision and sign-off

The employer either accepts or asks for more substantiation on cost or time. RICS describes this as repeating the analysis until agreement is reached or the change is dropped. It also notes that an instruction can sometimes be given before cost is agreed, to protect the programme.

If urgency forces you to start before the paperwork is finished, send a written note saying the work is proceeding pending formal approval. That keeps the record straight.

7. Carry out the work and close it out

Photograph the area before, during and after. Then close the entry: final value, completion date, and any drawings reissued. The CICV note recommends photographic or video evidence for exactly this reason.

Variation numbering: a simple system that works

RICS says any change by any party should go on a suitable register and be allocated a discrete number. It does not prescribe a format, so keep yours simple.

The format we suggest is job code, then type, then a running number. The example below is our own convention, not an industry standard.

Part Example Why it helps
Job code HIGH22 Ties the number to one job, so subbies never mix them up
Type VAR, RFI, SI Separates variations from RFIs and site instructions
Running number 007 Never reused, never skipped
Revision R1, R2 Shows a re-priced version without losing the original

So HIGH22-VAR-007-R1 is the first re-price of the seventh variation on the Highfield Road job. Quote that number in every email, photo caption and invoice line.

Two rules keep it clean. Withdrawn variations keep their number and are marked withdrawn, so the sequence has no holes. And the number goes on everything: the instruction, the quote, the drawings issued and the final account line.

For a ready-made layout, see our variation log template and variation order template.

What to log against every variation

A log only settles arguments if it has the dates. Record, per variation:

  • Number and short description
  • Who instructed it, and how (written, verbal then confirmed)
  • Date of instruction and date of notice
  • Date the price was submitted and date it was approved
  • Approved value and programme effect
  • Drawing or instruction reference
  • Status: proposed, priced, approved, instructed, complete, closed

RICS also says the register should be updated at least once a month, with copies of change documents and meeting minutes filed and follow-up actions chased. Make it a fixed slot in your monthly valuation routine. A variation that sits at “priced” for six weeks is a payment problem in waiting.

If you want the wider picture of tracking design changes alongside commercial ones, our design change tracking guide covers it.

Variation management best practices

The habits below separate jobs that get paid from jobs that end in argument.

Six practical habits for managing variations

Never start on a verbal instruction alone. Confirm it in writing before the work, or note that you are proceeding pending approval.

Know your conditions precedent. CMS notes that compliance with writing requirements may, subject to the contract, be a condition precedent to a claim. Such conditions are usually enforceable, so a claim made without compliance is likely to fail. Check your contract for notice windows and follow them to the letter.

Price time separately. If the change extends the programme, show the extra days as their own line rather than burying them in the rate.

One list per job. Variations, site instructions and RFIs should live together, so nobody has to search three inboxes and a WhatsApp group. See how this ties to reducing miscommunication on site.

Keep a tracker of site instructions. The CICV note recommends recording whether each one was given in writing. That column tells you at a glance where you are exposed.

Keep clients informed early. Most disputes about extras are really surprise disputes. Our piece on reducing disputes through client communication goes deeper.

Can a contractor refuse a variation?

It depends on the contract.

If there is no express right for the employer to instruct variations, the contractor can refuse without consequence. Under JCT, a contractor may make a reasonable objection to an instruction imposing restrictions on access, working space, working hours or the order of work.

On a JCT contract otherwise, a valid instruction has to be carried out, and you are entitled to fair payment. Under the JCT Intermediate Building Contract 2016, if the contractor does not comply within 7 days of the notice, the employer can bring in others and recover the cost. The same source says that where an instruction is not a proper one, the contractor is not entitled to payment for complying.

A change that alters the fundamental nature of the works may fall outside the variation clause altogether. In that case it can amount to a new contract needing new terms. If you are unsure whether an instruction is valid, speak to a construction solicitor or your trade body before you either refuse or proceed.

What to put in a variation letter

A variation letter, or instruction, authorises a change to the contracted scope and gives the basis for extra cost, omitted work or programme change. It should carry:

  • Instruction number and date
  • Who issued it and under which contract clause
  • A clear description of the change
  • Revised drawings and specifications
  • An approximate or agreed value
  • The programme impact
  • The valuation basis
  • An authorised signature

That list follows the typical contents of a variation instruction used on UK projects. On a domestic job, a one-page version with scope, price, days and two signatures does the job.

Perspective: why the approval trail should build itself

Most variations are lost in the gap between the site and the office. The client says yes in the kitchen, the photo goes in a WhatsApp group, and three weeks later nobody can find either.

We built BRCKS around that gap. It works like a simple chat. One tap on a message turns it into a variation, a snag, a materials order or a checklist item, and it lands in one list for the job. The photo, the date and the person are already attached.

Subcontractors and clients stay in WhatsApp and install nothing. They reply the way they always have, and the reply is filed against the right variation. That matters because a process people avoid is a process that fails on site.

We are builders at heart. The aim is to save site teams 30+ minutes a day of writing up at night, and to make sure the written trail exists before the work starts, not after the argument.

James

Run your variations in BRCKS

BRCKS is construction project management software for UK builders and contractors. The variations feature keeps instructions, RFIs and approvals with an audit trail, so each variation has a number, a status and its supporting files in one place. See how variation management software works on a live job.

BRCKS

Pricing is £40 per seat per month billed annually, or £50 monthly, and there is a 14-day free trial. Subcontractors and clients are free. Details are on the pricing page, or you can book a demo and see it with your own job set-up. Our document control guide shows how drawings, quotes and RAMS stay versioned alongside each variation.

FAQ

Who has to approve a variation?

The person named in your contract. That is the Contract Administrator or employer’s agent on a JCT job, the main contractor’s QS on a subcontract, and the homeowner on a domestic quote. Do not treat approval from anyone else as safe, however senior they sound on site.

Is a verbal instruction enough to be paid for extra work?

Not safely. Under JCT, contractors are generally not entitled to payment for varied work without formal written instruction, even if the employer approved it verbally. Confirm the instruction in writing the same day and keep a copy.

How often should I review the variation log?

At least monthly. RICS says the register should be updated at least once a month. On a busy job, a weekly check against site instructions catches unpriced changes before they pile up.

What if the client agrees to the work but not the price?

Agree the scope in writing and state that the price is to follow, or give a priced estimate and ask for written approval. Silence on price is not acceptance, so do not start extra work at the original rate unless that was explicitly agreed. Where the amount is large, take advice from a construction solicitor.

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How BRCKS Can Help

Mastering the variation approval process is essential for protecting your margins and maintaining clear communication with your clients. BRCKS simplifies this entire workflow by digitising documentation and automating approvals, ensuring that no change order ever slips through the cracks. By centralising your project data, our platform helps you mitigate risk and keep your site teams aligned with the office. We invite you to explore how BRCKS can streamline your construction management and help your business build with greater confidence. Learn more at BRCKS and explore our full feature set.


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